A tread compound for high-speed tires and its preparation method

Abstract

The present invention belongs to the field of rubber, and particularly relates to a tread rubber for high-speed tires and a method for preparing the same. Specifically, the present invention relates to a composition for preparing rubber and a method for preparing the same. The rubber obtained by the present invention exhibits high strength, excellent processing performance, good wear resistance, low heat generation, and superior high-speed performance, making it particularly suitable for use as a tread rubber for high-speed tires. Furthermore, the rubber preparation method of the present invention can reduce energy consumption and pollution compared to existing technologies, potentially generating significant economic and social benefits.

Description

Technical Field

[0001] The present invention belongs to the field of rubber, and in particular, relates to a composition for preparing rubber and a method for preparing rubber. The present invention also relates to rubber prepared by the composition or method. Background Art

[0002] In recent years, with the development of my country's economy, the automotive, construction machinery, and highway industries have also grown rapidly, leading to ever-increasing speeds for vehicles and mobile construction machinery. Simultaneously, human awareness of protecting their own lives and the environment has intensified. This has led to a strong demand for higher-performance tires, specifically those that are safe, durable, and environmentally friendly, while also placing higher demands on high-speed performance. Given the operational characteristics of high-speed tires, tread compound must maintain tread rigidity while also reducing overall heat generation to prevent delamination caused by excessive speed.

[0003] Currently, domestic research on high-strength and low-heating high-speed tire rubber primarily relies on modifying inorganic fillers with silane coupling agents and compounding them with rubber. Some reports have used submicron inorganic thermally conductive fillers in combination with carbon nanotube bundles, but this approach has limited success in reducing rubber heat buildup and significantly increases costs, hindering rubber application and cost control. Furthermore, the hydrolysis of the silane coupling agent during this modification process produces a large amount of ethanol. Ethanol is highly volatile at high temperatures, so this process generates significant amounts of ethanol vapor, which is released into the production environment. This not only negatively impacts the health of equipment operators but also poses a safety hazard to processing equipment due to its flammability and explosiveness. As a small molecule volatile organic compound, ethanol is a typical VOC (Volatile Organic Compound) emitter, and global attention is being focused on the pollution caused by VOC emissions. Therefore, the process of modifying inorganic fillers with silane coupling agents and compounding them with rubber is energy-intensive and highly polluting, posing significant environmental risks in future applications. Summary of the Invention

[0004] One of the purposes of the present invention is to provide a high-speed tire tread rubber with excellent performance while avoiding high energy consumption and high pollution process means.

[0005] The present invention uses a low-cost, green and environmentally friendly natural phenol compound - cardanol, which is emulsified into an emulsion by mixing with an emulsifier AES and is directly added to natural rubber latex for modification. During the high-temperature drying process, cardanol can react with the natural rubber molecular chain, which not only increases the cross-linking density, but also introduces a rigid group benzene ring, thereby achieving the purpose of improving the mechanical strength of natural rubber. The homemade low-heat elastomer can effectively enhance strength and reduce heat generation. In addition, the addition of vulcanizing agents, anti-scorching agents, accelerators, antioxidants, etc. for modification can not only ensure that the tire rubber has high strength, good process performance, and good wear resistance, but also ensure low heat generation and superior high-speed performance. The present invention does not use a silane coupling agent, thus avoiding environmental risks, and the materials required for preparation are cheap and easy to obtain, and the preparation process is simple. Furthermore, the present invention optimizes the rubber vulcanization process to further enhance the high-speed performance of the tread rubber.

[0006] In one aspect, the present application provides a composition for preparing rubber, which comprises, by weight: 100 parts of natural rubber, 0.5-1 part of cardanol (e.g., 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part), 5-10 parts of emulsifier AES (e.g., 5, 6, 7, 8, 9 or 10 parts), 6-13 parts of homemade low heat buildup elastomer (e.g., 6, 7, 8, 9, 10, 11, 12 or 13 parts), formaldehyde resin CF 0.5-1 part (for example, 0.5, 0.6, 0.7, 0.8, 0.9 or 1.0 part), carbon black 18-25 parts (for example, 18, 19, 20, 21, 22, 23, 24 or 25 parts), white carbon black 6-9 parts (for example, 6, 7, 8 or 9 parts), high temperature wax 1-2 parts (for example, 1, 1.5 or 2 parts), antioxidant 1-2 parts (for example, 1, 1.5 or 2 parts), insoluble sulfur HDOT-20 1.5-2 parts (for example, 1.5, 1.6, 1.7, 1.8, 1.9 or 2 parts), accelerator 1.5-2.5 parts (for example, 1.5, 2 or 2.5 parts), zinc oxide 2-4 parts (for example, 2, 3 or 4 parts), stearic acid 2-3 parts (for example, 2, 2.5 or 3 parts);

[0007] The low heat build-up elastomer is a blend of ethylene propylene diene monomer (EPDM) grafted maleic anhydride (MAH), styrene-butadiene-styrene block copolymer (SBS), and nano-B4C;

[0008] The low heat build-up elastomer is prepared by a preparation method comprising the following steps:

[0009] (1) Weigh 80-100 parts (e.g., 80, 85, 90, 95 or 100 parts) of EPDM-g-MAH (preferably Dow DM-7, with a maleic anhydride grafting rate of 0.7% to 1.18% (e.g., 0.7%, 0.8%, 0.9%, 1.0%, 1.1% or 1.18%)), 80-100 parts (e.g., 80, 85, 90, 95 or 100 parts) of SBS elastomer, and 10-20 parts (e.g., 10, 15 or 20 parts) of nano-B4C for later use;

[0010] (2) Setting the temperature of the torque rheometer to 120°C to 130°C and the rotor speed to 50 rpm to 70 rpm (e.g., 50 rpm, 60 rpm, or 70 rpm), sequentially adding SBS, nano-B4C, and EPDM-g-MAH, mixing for 15 min to 20 min, and then removing;

[0011] The carbon black is selected from N326, N660 or a combination thereof;

[0012] The antioxidant is selected from RD, 4020, 4030, DFC-34 or any combination thereof;

[0013] The accelerator is selected from DPG, Carbowax, NS or any combination thereof.

[0014] The cardanol used in the present invention is a kind of unsaturated or saturated long carbon chain (-C 15 H 27-31 Cardanol is a monophenol compound with an unsaturated or saturated long carbon chain at the meta position of the hydroxyl group. Cardanol reacts with natural rubber molecular chains, not only increasing the crosslink density but also introducing a rigid group, benzene rings, thereby enhancing the mechanical strength of natural rubber.

[0015] The emulsifier AES used in the present invention is an anionic surfactant with excellent performance, and its main components are sodium lauryl sulfate and sodium laureth sulfate.

[0016] The formaldehyde resin CF used in the present invention refers to cresol-formaldehyde resin.

[0017] In this article, N326 and N660 are carbon black brands, RD, 4020, 4030, and DFC-34 are antioxidant brands, DPG, Carbowax, and NS are accelerator brands, and HDOT-20 is an insoluble sulfur brand. The above reagents are all commercially available conventional products. The names and CAS numbers of some of the reagents are as follows:

[0018]

[0019]

[0020] In one aspect, the present application provides a method for preparing rubber, comprising using the composition of the present invention as a raw material; the method comprises the following steps:

[0021] Step 1: Modify natural rubber with cardanol to make raw rubber;

[0022] Step 2: Make your own low-heat elastomer;

[0023] Step 3: mixing the raw rubber obtained in step 1 with the low heat buildup elastomer, carbon black, white carbon black, high temperature wax, zinc oxide, and formaldehyde resin CF obtained in step 2 to obtain a primary mixed rubber;

[0024] Step 4: Mix the primary rubber mix with insoluble sulfur HDOT-20, accelerator, and scorch retarder to obtain a secondary rubber mix; send the secondary rubber mix to the open mixing mill for thinning;

[0025] Step 5: vulcanizing the secondary rubber mix under heating conditions to obtain vulcanized rubber;

[0026] The step 1 and step 2 can be performed sequentially or simultaneously.

[0027] In certain embodiments, step one comprises:

[0028] Step 1-1:

[0029] The cardanol and the emulsifier AES are dissolved in water to prepare an aqueous solution containing 8% to 10% (e.g., 8%, 9% or 10%) of cardanol, and the solution is emulsified to obtain a cardanol emulsion; natural rubber is prepared into a natural latex having a solid content of 30% to 40% (e.g., 30%, 32%, 34%, 36%, 38% or 40%), and the cardanol emulsion is slowly added to the stirred natural rubber for a modification reaction; preferably, the stirring rate is 300 to 400 r / min; preferably, the modification reaction time is 60 to 120 min;

[0030] Step 1-2: After the reaction is completed, the rubber is flocculated and solidified using a formic acid aqueous solution; preferably, the concentration of the formic acid aqueous solution is 5% to 6%; preferably, the flocculation and solidification time is 1 to 2 hours; the flocculated and solidified rubber is crushed and shredded into rubber particles, and the rubber particles are soaked in deionized water to remove formic acid; in certain embodiments, this step is: the modified natural rubber is placed in a tray, flocculated and solidified using a 5% to 6% formic acid aqueous solution; after standing for 1 hour, the rubber is crushed and shredded into (15×10×10) mm 3 The rubber particles were soaked in deionized water for 24 h to remove formic acid;

[0031] Step 1-3: subjecting the rubber particles to a high-temperature treatment at 104-106° C. (e.g., 105° C.), preferably for 1-2 hours, preferably in a forced air drying oven; then, the rubber particles are sliced on a two-roll mill with a thickness of 1-3 mm (e.g., 2 mm), and then dried to a constant weight (e.g., for 2 hours) to obtain raw rubber.

[0032] In certain embodiments, step two comprises:

[0033] Step 2-1: Weigh 80-100 parts of EPDM-g-MAH (preferably Dow DM-7, with a maleic anhydride grafting rate of 0.7% to 1.18%), 80-100 parts of SBS elastomer, and 10-20 parts of nano-B4C for later use;

[0034] Step 2-2: Set the temperature of the torque rheometer to 120°C to 130°C and the rotor speed to 50 rpm to 70 rpm, add SBS, nano-B4C and EPDM-g-MAH in sequence, mix for 15 min to 20 min, and take out.

[0035] In certain embodiments, step three comprises:

[0036] Step 3-1: Weigh the raw rubber obtained in step 1, the low-heat elastomer, carbon black, white carbon black, and high-temperature wax obtained in step 2 according to the formula, add them to an internal mixer and mix them at a rotor speed of 55-60 r / min. When the temperature reaches 134-136°C (e.g., 135°C), proceed to the next step;

[0037] Step 3-2: Add zinc oxide and formaldehyde resin and continue mixing at a rotor speed of 55-60 r / min. When the temperature reaches 144-146°C (e.g., 145°C), proceed to the next step;

[0038] Step 3-3: Raise the ejector pin to the middle position for 5 to 6 seconds, at which time adjust the rotor speed to 45 to 50 r / min; raise the ejector pin to the highest position, maintain the rotor speed at 45 to 50 r / min, and wait until the temperature reaches 154 to 156°C (e.g., 155°C) before draining the rubber to obtain a primary mixed rubber.

[0039] In certain embodiments, step four comprises:

[0040] Step 4-1: Add the primary rubber mix at a rotor speed of 25-30 r / min and mix for 28-32 s (e.g., 30 s); add insoluble sulfur HDOT-20, accelerator, and scorch retarder at a rotor speed of 25-30 r / min, and wait for the temperature to rise to 89-91°C (e.g., 90°C) before proceeding to the next step;

[0041] Step 4-2: Move the ejector pin to the middle position, maintain the rotor speed at 25-30 r / min, and wait for the temperature to rise to 102-104°C (e.g., 103°C) before draining to obtain the secondary mixed rubber;

[0042] Step 4-3: After the secondary mixed rubber is discharged from the internal mixer, it is sent to the open mixer and thinned three times to a thickness of 2 to 3 mm.

[0043] In certain embodiments, in step five, the vulcanization temperature is 137-139° C. (eg, 138° C.), and the vulcanization time is 35-40 min.

[0044] In one aspect, the present application provides a rubber obtained from any one of the above compositions or preparation methods.

[0045] The present invention modifies natural rubber using cardanol, an inexpensive, environmentally friendly natural phenolic compound, as well as a vulcanizing agent, a scorch retarder, an accelerator, an antioxidant, and a self-made low-heat-generation elastomer. Through ingredient preparation, mastication, mixing, and extrusion, a high-speed tire tread rubber is produced that not only ensures high tire strength, excellent processability, and wear resistance, but also low heat generation and superior high-speed performance. The materials required for this preparation are inexpensive and readily available, and the preparation process is simple.

[0046] In certain embodiments, the rubbers of the present invention have one or more of the following characteristics:

[0047] (1) Tensile strength: 29-35 MPa (e.g., 30-34 MPa);

[0048] (2) Elongation at break: 540% to 570% (e.g., 550% to 557%);

[0049] (3) 300% modulus of elongation: 21-23 MPa;

[0050] (4) tanδ (dielectric loss angle) at 60°C: 0.07 to 0.09;

[0051] (5) Akron wear volume (cm 3 ): 0.19~0.25 (for example 0.20~0.23).

[0052] The above parameters can be measured by conventional methods in the art, such as the methods described in GB / T 528-2009 or GB / T 1689-2015.

[0053] In one aspect, the present application provides a use of the rubber of the present invention for preparing a tire. In certain embodiments, the rubber is used for a tread rubber of a tire.

[0054] In one aspect, the present application provides a product comprising the rubber of the present invention, or made from the rubber of the present invention. In certain embodiments, the product is selected from tires, rubber tracks, conveyor belts, and shock absorbers.

[0055] The present application also provides a vehicle or engineering machinery, which comprises the tire of the present invention.

[0056] Advantageous Effects of the Invention

[0057] The tread rubber for high-speed tires provided by the present invention has the following advantages:

[0058] (1) The raw rubber system uses cardanol to modify natural rubber to obtain high-strength natural rubber, and the reinforcement system uses a high-wear-resistant carbon black / white carbon black combined system. On the basis of ensuring the tensile properties of the rubber, the tanδ of the rubber at 60°C is reduced and the heat generation is reduced;

[0059] (2) Adding self-made low-heat elastomer can further improve the heat generation performance of the rubber compound and enhance its strength and wear resistance;

[0060] (3) The tensile stress and tensile properties of the vulcanized rubber meet the rigidity matching requirements of the tread of high-speed engineering machinery tires, and the heat generation performance and wear resistance can adapt to the operating characteristics of high-speed engineering machinery tires. DETAILED DESCRIPTION

[0061] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be obtained commercially.

[0062] Example 1

[0063] A rubber for high-speed tires, characterized by: 100 parts of natural rubber NR, 0.5 parts of cardanol, 5 parts of emulsifier AES, 8 parts of self-made low-heat-generating elastomer, 0.5 parts of formaldehyde resin CF, 25 parts of carbon black N326, 9 parts of white carbon black, 2 parts of high-temperature wax, 2 parts of antioxidant 4020, 2 parts of insoluble sulfur HDOT-20, 2 parts of accelerator DPG, 3 parts of zinc oxide, and 3 parts of stearic acid.

[0064] Specific implementation of the tread rubber for high-speed tires:

[0065] Step 1:

[0066] According to the formula, a certain amount of cardanol and emulsifier AES were weighed and dissolved in water to prepare an aqueous solution containing 10% cardanol, which was then added to an emulsifier for mixing and emulsification. After 10 minutes, a cardanol emulsion was obtained. Natural rubber was prepared into a natural latex with a solid content of 30%, which was placed in a stirring tank and stirred at a speed of 300r / min. The prepared cardanol emulsion was slowly added to the high-speed stirred natural rubber, and then the modification reaction was carried out for 60 minutes. After the reaction was completed, the modified natural rubber was placed in a tray and flocculated and solidified with a 5% formic acid aqueous solution. After standing for 1 hour, it was creped and cut into (15×10×10) mm pieces. 3 The rubber particles were soaked in deionized water for 24 hours to remove formic acid. The rubber particles were subjected to a high-temperature treatment at 105°C in a forced air drying oven for 2 hours. The rubber particles were then sheeted on a two-roll mill with a thickness of 2 mm and dried for another 2 hours to constant weight to obtain the raw rubber.

[0067] Step 2:

[0068] Weigh 100 parts of EPDM-g-MAH sample (Dow DM-7, maleic anhydride grafting rate 0.7% to 1.18%), 100 parts of SBS elastomer, and 15 parts of nano-B4C. Set the temperature of the torque rheometer to 120°C and the rotor speed to 60 rpm. Add SBS, nano-B4C and EPDM-g-MAH in sequence, mix for 20 minutes, and take out.

[0069] Step 3:

[0070] Weigh the raw rubber obtained in step 1 and the homemade low-heat elastomer, carbon black, white carbon black, and high-temperature wax obtained in step 2 according to the formula, add them to the internal mixer and mix them at a rotor speed of 60 r / min until the temperature reaches 135°C. Add zinc oxide and formaldehyde resin and continue mixing at a rotor speed of 60 r / min until the temperature reaches 145°C. Raise the top bolt to the middle position and hold for 5 seconds. At this time, adjust the rotor speed to 50 r / min; raise the top bolt to the highest position and maintain the rotor speed at 50 r / min. Wait until the temperature rises to 155°C, drain the rubber, and obtain the primary rubber mix.

[0071] Step 4:

[0072] The rubber mix from the third step was added and mixed at a rotor speed of 30 r / min for 30 seconds. Sulfur, accelerator NS, and scorch retarder were added and the rotor speed was maintained at 30 r / min. When the temperature reached 90°C, the next step was initiated. The ejector bolt was moved to the neutral position and the rotor speed was maintained at 30 r / min. When the temperature reached 103°C, the rubber mix was discharged to obtain the second rubber mix. After discharge from the internal mixer, the second rubber mix was sent to an open mixer and thinned three times to a thickness of 3 mm.

[0073] Step 5:

[0074] The secondary mixed rubber is vulcanized at high temperature to prepare vulcanized rubber, the vulcanization temperature is 138°C, and the vulcanization time is 40 minutes.

[0075] Example 2

[0076] A rubber for high-speed tires, characterized by: 100 parts of natural rubber NR, 1 part of cardanol, 10 parts of emulsifier AES, 10 parts of self-made low-heat-generating elastomer, 1 part of formaldehyde resin CF, 25 parts of carbon black N660, 9 parts of white carbon black, 2 parts of high-temperature wax, 2 parts of antioxidant 4030, 2 parts of insoluble sulfur HDOT-20, 2.5 parts of accelerator NS, 3 parts of zinc oxide, and 3 parts of stearic acid.

[0077] Specific implementation of the tread rubber of the high-speed tire:

[0078] Step 1:

[0079] According to the formula, a certain amount of cardanol and emulsifier AES were weighed and dissolved in water to prepare an aqueous solution containing 10% cardanol, which was then added to an emulsifier for mixing and emulsification. After 10 minutes, a cardanol emulsion was obtained. Natural rubber was prepared into a natural latex with a solid content of 30%, which was placed in a stirring tank and stirred at a speed of 300r / min. The prepared cardanol emulsion was slowly added to the high-speed stirred natural rubber, and then the modification reaction was carried out for 60 minutes. After the reaction was completed, the modified natural rubber was placed in a tray and flocculated and solidified with a 5% formic acid aqueous solution. After standing for 1 hour, it was creped and cut into (15×10×10) mm pieces. 3 The rubber particles were soaked in deionized water for 24 hours to remove formic acid. The rubber particles were subjected to a high-temperature treatment at 105°C in a forced air drying oven for 2 hours. The rubber particles were then sheeted on a two-roll mill with a thickness of 2 mm and dried for another 2 hours to constant weight to obtain the raw rubber.

[0080] Step 2:

[0081] Weigh 100 parts of EPDM-g-MAH sample (Dow DM-7, maleic anhydride grafting rate 0.7% to 1.18%), 100 parts of SBS elastomer, and 15 parts of nano-B4C. Set the temperature of the torque rheometer to 120°C and the rotor speed to 60 rpm. Add SBS, nano-B4C and EPDM-g-MAH in sequence, mix for 20 minutes, and take out.

[0082] Step 3:

[0083] Weigh the raw rubber obtained in step 1 and the homemade low-heat elastomer, carbon black, white carbon black, and high-temperature wax obtained in step 2 according to the formula, add them to the internal mixer and mix them at a rotor speed of 60 r / min until the temperature reaches 135°C. Add zinc oxide and formaldehyde resin and continue mixing at a rotor speed of 60 r / min until the temperature reaches 145°C. Raise the top bolt to the middle position and hold for 5 seconds. At this time, adjust the rotor speed to 50 r / min; raise the top bolt to the highest position and maintain the rotor speed at 50 r / min. Wait until the temperature rises to 155°C, drain the rubber, and obtain the primary rubber mix.

[0084] Step 4:

[0085] The rubber mix from the third step was added and mixed at a rotor speed of 30 r / min for 30 seconds. Sulfur, accelerator NS, and scorch retarder were added and the rotor speed was maintained at 30 r / min. When the temperature reached 90°C, the next step was initiated. The ejector bolt was moved to the neutral position and the rotor speed was maintained at 30 r / min. When the temperature reached 103°C, the rubber mix was discharged to obtain the second rubber mix. After discharge from the internal mixer, the second rubber mix was sent to an open mixer and thinned three times to a thickness of 3 mm.

[0086] Step 5:

[0087] The secondary mixed rubber is vulcanized at high temperature to prepare vulcanized rubber, the vulcanization temperature is 138°C, and the vulcanization time is 40 minutes.

[0088] Comparative Example 1

[0089] This embodiment is made of the following raw materials in parts by weight: 100 parts of natural rubber, 25 parts of carbon black N326, 9 parts of white carbon black, 2 parts of high-temperature wax, 3 parts of zinc oxide, 2 parts of stearic acid, 2 parts of sulfur, 1.5 parts of accelerator DPG, 1 part of antioxidant 4020, and 2 parts of silane coupling agent.

[0090] Place the raw rubber in an open rubber mixer and plasticize for 4 minutes. Once the rubber is rolled, add the antioxidant, zinc oxide, stearic acid, carbon black, white carbon black, high-temperature wax, and silane coupling agent and mix. Once the rubber is fully powdered, roll it into triangles several times. Finally, add sulfur and accelerator, adjust the roller gap to 2mm, and release the sheet. After the sheet is left for 24 hours, place it in a mold and vulcanize it on a flat vulcanizer at 155°C for 12 minutes.

[0091] Performance testing was carried out in accordance with GB / T 528-2009, GB / T 1689-2015 and other standards. The results are shown in Table 1:

[0092] Table 1 Rubber performance test results

[0093] Project Name Example 1 Example 2 Comparative Example 1 Tensile strength / MPa 30.7 33.5 24.5 Elongation at break / % 550.8 556.7 488.4 300% modulus of tensile stress / MPa 22.3 21.6 17.7 tanδ at 60℃ 0.086 0.072 0.195 <![CDATA[Akhron wear volume (cm 3 )]]> 0.23 0.20 0.29

[0094] Although the specific embodiments of the present invention have been described in detail, those skilled in the art will understand that various modifications and variations can be made to the details based on all the teachings disclosed, and these changes are within the scope of protection of the present invention. The full scope of the present invention is given by the appended claims and any equivalents thereof.

Claims

1. A composition for preparing rubber, comprising, by weight: 100 parts of natural rubber, 0.5-1 part of cardanol, 5-10 parts of emulsifier AES, 6-13 parts of self-made low-heat-generation elastomer, 0.5-1 part of formaldehyde resin CF, 18-25 parts of carbon black, 6-9 parts of white carbon black, 1-2 parts of high-temperature wax, 1-2 parts of antioxidant, 1.5-2 parts of insoluble sulfur HDOT-20, 1.5-2.5 parts of accelerator, 2-4 parts of zinc oxide, and 2-3 parts of stearic acid; The low heat build-up elastomer is a blend of EPDM rubber grafted with maleic anhydride, styrene-butadiene-styrene block copolymer, and nano-B4C; The low heat build-up elastomer is prepared by a preparation method comprising the following steps: (1) Weigh 80-100 parts of EPDM-g-MAH, 80-100 parts of SBS elastomer, and 10-20 parts of nano-B4C for later use; (2) Set the temperature of the torque rheometer to 120°C to 130°C and the rotor speed to 50 rpm to 70 rpm, add SBS, nano-B4C and EPDM-g-MAH in sequence, mix for 15 min to 20 min, and take out; The carbon black is selected from N326, N660 or a combination thereof; The antioxidant is selected from RD, 4020, 4030, DFC-34 or a combination thereof; The accelerator is selected from DPG, Carbowax, NS or a combination thereof.

2. The composition for preparing rubber according to claim 1, wherein the EPDM-g-MAH is Dow DM-7 from the United States, and the maleic anhydride grafting rate is 0.7% to 1.18%.

3. A method for preparing rubber, comprising using the composition according to claim 1 or 2 as a raw material; the method comprising the following steps: Step 1: Modify natural rubber with cardanol to make raw rubber; Step 2: Make your own low-heat elastomer; Step 3: mixing the raw rubber obtained in step 1 with the low heat buildup elastomer, carbon black, white carbon black, high temperature wax, zinc oxide, and formaldehyde resin CF obtained in step 2 to obtain a primary mixed rubber; Step 4: Mix the primary rubber mix with insoluble sulfur HDOT-20, accelerator, and scorch retarder to obtain a secondary rubber mix; send the secondary rubber mix to the open mixing mill for thinning; Step 5: vulcanizing the secondary rubber mix under heating conditions to obtain vulcanized rubber; The step 1 and step 2 can be performed sequentially or simultaneously.

4. The method of claim 3, wherein step 1 comprises: Step 1-1: dissolving the cardanol and the emulsifier AES in water to prepare an aqueous solution containing 8% to 10% cardanol and emulsifying the solution to obtain a cardanol emulsion; preparing natural rubber into a natural latex having a solid content of 30% to 40%, and slowly adding the cardanol emulsion to the stirred natural rubber to carry out a modification reaction; Step 1-2: After the reaction is completed, the rubber is flocculated and solidified using a formic acid aqueous solution; the flocculated and solidified rubber is crushed and shredded to form rubber particles, and the rubber particles are soaked in deionized water to remove the formic acid; Step 1-3: subjecting the rubber particles to a high-temperature treatment at 104-106° C., then sheeting the rubber particles on a two-roll mill with a thickness of 1-3 mm, and drying the sheets to a constant weight to obtain raw rubber.

5. The method of claim 4, wherein in step 1-1, the stirring rate is 300 to 400 r / min.

6. The method of claim 4, wherein in step 1-1, the modification reaction time is 60 to 120 minutes.

7. The method of claim 4, wherein in step 1-2, the concentration of the formic acid aqueous solution is 5% to 6%.

8. The method of claim 4, wherein in step 1-2, the flocculation and solidification time is 1 to 2 hours.

9. The method of claim 4, wherein in steps 1-3, the high temperature treatment is performed for 1 to 2 hours.

10. The method of claim 3, wherein step 2 comprises: Step 2-1: Weigh 80-100 parts of EPDM-g-MAH, 80-100 parts of SBS elastomer, and 10-20 parts of nano-B4C for later use; Step 2-2: Set the temperature of the torque rheometer to 120°C to 130°C and the rotor speed to 50 rpm to 70 rpm, add SBS, nano-B4C and EPDM-g-MAH in sequence, mix for 15 min to 20 min, and take out.

11. The method according to claim 10, wherein the EPDM-g-MAH is Dow DM-7, and the maleic anhydride grafting rate is 0.7% to 1.18%.

12. The method of claim 3, wherein step three comprises: Step 3-1: Weigh the raw rubber obtained in step 1, the low-heat elastomer, carbon black, white carbon black, and high-temperature wax obtained in step 2 according to the formula, add them into an internal mixer and mix them at a rotor speed of 55-60 r / min. When the temperature reaches 134-136°C, proceed to the next step; Step 3-2: Add zinc oxide and formaldehyde resin and continue mixing at a rotor speed of 55-60 r / min. When the temperature reaches 144-146°C, proceed to the next step; Step 3-3: Raise the ejector pin to the middle position for 5 to 6 seconds, at which time adjust the rotor speed to 45 to 50 r / min; raise the ejector pin to the highest position, maintain the rotor speed at 45 to 50 r / min, and wait until the temperature rises to 154 to 156°C before draining the rubber to obtain a mixed rubber.

13. The method of claim 3, wherein said step 4 comprises: Step 4-1: Add the primary rubber mix at a rotor speed of 25-30 r / min and mix for 28-32 seconds; add insoluble sulfur HDOT-20, accelerator, and scorch retarder at a rotor speed of 25-30 r / min and proceed to the next step when the temperature rises to 89-91°C; Step 4-2: Move the ejector pin to the middle position, maintain the rotor speed at 25-30 r / min, and wait until the temperature reaches 102-104°C to discharge the rubber to obtain the secondary rubber mix; Step 4-3: After the secondary mixed rubber is discharged from the internal mixer, it is sent to the open mixer and thinned three times to a thickness of 2 to 3 mm.

14. The method according to any one of claims 3 to 13, wherein in step 5, the vulcanization temperature is 137-139°C, and the vulcanization time is 35-40 minutes.

15. A rubber obtained from the composition of claim 1 or 2 or the method of any one of claims 3 to 14.

16. The rubber of claim 15, having one or more of the following characteristics: (1) Tensile strength: 29-35 MPa; (2) Elongation at break: 540% to 570%; (3) 300% modulus of elongation: 21-23 MPa; (4) tanδ at 60°C: 0.07-0.09, where δ is the dielectric loss angle; (5) Akron wear volume: 0.19-0.25 cm 3 .

17. Use of the rubber according to claim 15 or 16 for the production of tyres.

18. The use according to claim 17, wherein the rubber is used as a tread rubber for tires.

19. A product comprising or made from the rubber of claim 15 or 16.

20. The product of claim 19, selected from the group consisting of tires, rubber tracks, conveyor belts, and shock absorbers.

21. A vehicle or construction machinery comprising the tire according to claim 20.

Images